Backed up by a brief from the Trump administration’s Department of Justice, Masterpiece will almost certainly focus on another part of the First Amendment: the free speech clause. The shop is arguing that, given the artistry involved in creating a custom wedding cake, compelling it to create a cake for a ceremony it morally disapproves of would violate its rights to freedom of speech and expression.

Creating religious exceptions to generally applicable laws would make civil rights statutes very difficult to enforce, since discrimination based on race, gender, or sexual orientation can all be defended on religious grounds. If applied logically, a religious exemption would quickly mean that civil rights laws exist only at the pleasure of the employer.

Recognizing this liability in a free expression argument, Masterpiece will likely claim that a free expression exemption applies only in the very narrow context of a mom-and-pop bakery being asked to make something for a particular ceremony. Most employees of most companies, they will argue, are not engaged in activity that is similarly expressive.

But as the libertarian legal scholars Dale Carpenter and Eugene Volokh argue in their persuasive amicus brief on behalf of Colorado, if Masterpiece’s free speech claim were accepted by the Court, it would “apply to a vast range of conduct.” Many of the activities employees and their supervisors engage in on the job have elements as potentially “expressive” as baking a cake, and this is true of both tiny storefronts and Fortune 500 corporations. “[Restaurant chain] Subway calls its sandwich-makers ‘sandwich artists,’” Carpenter and Volokh observe, “[b]ut a restaurant may not refuse to cook or prepare a table for certain customers on the ground that it would be a free speech compulsion.” Similarly, a florist who didn’t want to participate in a same-sex wedding could declare themselves “floral artists,” hotel receptionists could declare themselves “phone answering artists,” and so on.

It is unclear about where the line would end up being drawn should the Court accept Masterpiece’s free speech argument. But even if it ended up being fairly narrow, it would still require extensive litigation to find out. And it’s likely that in practice the exceptions would not be narrow at all. The wise approach for the Supreme Court would be to follow the lead of the Colorado court and uphold the sound judgement of the state’s civil rights commission: that while Jack Phillips is entitled to his beliefs, when he opens a business to the public he is required to follow state laws and treat his customers equally.

The idea here is a classic Alito-style pincer operation in which an apparently narrow argument gets broader and broader. And if it takes a lot of litigation to sort out, that means “state governments and civil rights groups using scarce resources that could otherwise be used to actually enforce civil rights laws.”